Formerly known as Ansar Beit al-Maqdis, an Egyptian militant group that claims affiliation to the Islamic State has claimed responsibility for simultaneous and well-coordinated attacks that killed 25 soldiers and one policeman across three towns in the Sinai Peninsula on Thursday.

Recently changing its name to Sinai Province, or Waliyat Sinai, the militant group carried out a car bombing outside a military base and pounded the base with mortars – toppling some buildings and leaving soldiers buried under the debris.

Along with the military base that was hit, the other attacks included mortar rounds fired at a hotel, a police club and more than a dozen checkpoints, officials said. The militants struck the Northern Sinai provincial capital el-Arish, the nearby town of Sheik Zuwayid and the town of Rafah bordering Gaza.

Just a few hours before carrying out the attacks, the group posted a photo of masked militants dressed in black on Twitter. They carried rocket-propelled grenades in a show of force, while flying the Islamic State black flag in the background. In the Twitter post, they said it was “an extensive simultaneous offensive for the soldiers of the caliphate” and listed at least eight checkpoints that also came under attack in the three locations.

The Thursday attacks left at least 60 people wounded, and confirming the death toll of 26, medical officials said the death toll is expected to rise. The explosions had smashed windows and shook residential areas in el-Arish. Electricity went off across the city.

Thursday’s attacks are expected to cause a great deal of embarrassment to the government and military after nearly a yearlong offensive in Sinai aimed at uprooting Islamic militants.